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Lpc55s69jbd100 FirmwareOperating system · Nxp

CVE-2021-40154

MEDIUM · 5.5 CVSS v3.1 Published 2021-12-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
57/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
NXP LPC55S69 devices before A3 have a buffer over-read via a crafted wlength value in a GET Descriptor Configuration request during use of USB In-System Programming (ISP) mode. This discloses protected flash memory.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

NXP LPC55S69 microcontrollers before version A3 contain a buffer over-read vulnerability in the USB In-System Programming (ISP) mode. By sending a crafted GET Descriptor Configuration request with a malicious wlength value, an attacker can read beyond buffer boundaries and extract protected flash memory content.

MitigationUpdate LPC55S69 firmware to version A3 or later. If USB ISP is not required in production, disable it. Restrict physical access to USB programming interfaces and consider network segmentation for devices with active USB ISP.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Lpc55s69jbd100 FirmwareOperating system
Affected:all versions
Lpc55s69jbd64 FirmwareOperating system
Affected:all versions
Lpc55s69jev98 FirmwareOperating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the exact LPC55S69 part number
    Inspect the device BOM, schematics, or physical chip markings to confirm the specific variant (LPC55S69JBD100, LPC55S69JBD64, or LPC55S69JEV98)
    Affected if The part number matches one of the affected variants (JBD100, JBD64, JEV98)
  2. Determine the installed firmware version
    Connect to the device via debug interface (SWD/JTAG) and read the firmware version from flash memory, or check the firmware version if exposed via diagnostic API or bootloader version string
    Affected if Firmware version is earlier than A3, or version cannot be determined and falls within the affected range
  3. Check if USB ISP mode is enabled
    Inspect the device configuration bytes or boot configuration settings to determine whether USB ISP is enabled as a boot option; this is typically controlled by boot mode pins or flash configuration bits
    Affected if USB ISP mode is enabled and the device is configured to enter USB ISP on boot or reset
  4. Verify USB descriptor configuration
    If USB ISP is active, analyze the USB stack configuration to inspect how the GET Descriptor Configuration request is handled, specifically the wLength parameter handling
    Affected if The USB ISP firmware processes wLength values without proper bounds checking, allowing over-read conditions
  5. Confirm USB ISP is exposed
    Check whether the USB programming interface is accessible in the deployment environment (exposed USB ports, physical access possibility)
    Affected if USB ISP functionality is accessible and the device can enter programming mode

A user is affected if their device uses an LPC55S69 variant (JBD100, JBD64, or JEV98) with firmware versions before A3 and has USB ISP mode enabled, as this combination allows the buffer over-read to occur during USB descriptor handling.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update LPC55S69 firmware to version A3 or later. If USB ISP is not required in production, disable it. Restrict physical access to USB programming interfaces and consider network segmentation for devices with active USB ISP.

Recommended fix Moderate confidence

NXP LPC55S69 firmware version A3 or later

  1. 1. Identify the current firmware version of the NXP LPC55S69 device by querying the device or reviewing firmware documentation.
  2. 2. Obtain the A3 or later firmware version from NXP's official firmware distribution channels (typically via NXP's website or designated support contacts).
  3. 3. Follow NXP's standard firmware update procedure to flash the updated firmware onto the LPC55S69 device.
  4. 4. After updating, verify the firmware version has been successfully applied.
  5. 5. As an additional mitigation, if USB ISP mode is not required in production, disable it to reduce the attack surface.
Caveat Firmware updates on microcontrollers may require recalibration or could affect custom bootloader implementations; test thoroughly in development environment before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Lpc55s69jbd100 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
25.0 hours of engineering $4,400
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-40154 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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